private void addNode(GraphNode graphNode) { if (graphNodeMap == null) { graphNodeMap = new HashMap<String, GraphNode<?>>(); } else { final AttributeNode old = graphNodeMap.get(graphNode.getRegistrationName()); if (old != null) { log.debugf( "Encountered request to add entity graph node [%s] using a name [%s] under which another " + "node is already registered [%s]", old.getClass().getName(), graphNode.getRegistrationName(), graphNode.getClass().getName()); } } graphNodeMap.put(graphNode.getAttributeName(), graphNode); }